(skip to the bottom for CAD links)
Hope you like my latest creation! In poking around 1678’s CAD I noticed their drive gearboxes were really cool. I really liked the overall design and the form of their drive gearboxes (What happened to ballshiftsohard??!), so after cadding up my own gearbox in the same style, I thought it was cool but would be cautious to use it on a competition robot in a typical game because it couldn’t shift and only had 2 CIMs. From there, I thought if it had 3 CIMS and could stay similar in size/simplicity it would be something more suited for my team to try on our offseason bot and maybe a season bot. My first step was research, and what did I find? Chak already did that. And it’s really cool. And I don’t understand what’s going on in half of it.
Chak’s awesome design is linked here, for anyone interested:
But I had been pretty sick for a week and really needed a design project to kill another day or two before I could go back to work, and I thought with the rise of 775pro drivetrain gearboxes it might be cool to design one of my own. My primary goal was (beyond the obvious light, functional, as small as possible, etc) to design a gearbox that could completely fit under the top surface of a tube, without the need for a gearbox slot in the bellypan.
I ended up with this gearbox, and sitting nicely at 1.9" tall (stolen from my largest gear’s OD from vex) it’s definitely the coolest gearbox I’ve designed.
Some variability in the sprockets could vary the gearbox speeds across different designs, but a realistic sample is a 16 and a 22 tooth sprocket from VP or whoever end up with a 14.98 adjusted speed from JVN.
My next iteration will be a very similar gearbox with everything (but the motors ofc) inside of a 2x2 along (imagine the plates replaced with a two by two) with sprockets, and I guess we will then have a design for gearbox and chain in tube!
Anyways, Here is the Onshape link:
And a google drive link with a STEP:
As always, questions and feedback are appreciated!